Gold sound track in motion picture film



Patented Nov. 18, 1941 corn scum) TRACK IN MOTION PICTURE FILM LeopoldD; Marines, Rochester, N. Y., and Leopold Godowsky, Jr Westport; Conn.,assignors to Eastman Kodak Company, Rochester, corporation of New JerseyN. Y., a

No Drawing. Application October 5, 1939, Serial 4 Claims.

The invention relates to a method of recording sound in photographicmaterials and especially to the recording of sound in multi-layermaterials for colour photography.

The recording of sound on motion picture film containing a plurality oflayers which are processed to colour has heretofore presenteddifliculties, due to insufficient absorption by any of the In GreatBritain January 23,-

three dye images of light in the region to which I the photo-electriccell is sensitive. Moreover, the characteristics of contrast and densitydesirable for the sound track are seldom compatible for those requiredfor optimum picture quality, and this is "particularly true where themulti-layer material is processed by reversal. In copying the soundtrack, moreover, it is generally considered desirable to form thepositive sound track by' printing from a negative rather than to printfrom a master positive and then to reverse the printed image.

Various methods have been proposed for the production of sound trackimages in multi-layer photographic film one of which is described in ourprior U. S. Patent 2,143,787, granted January 10, 1939, in which thesound image is formed of silver sulfide. The disadvantage of thisprocess is that a negative sound image cannot be formed directly (or apositive image in the caseof a print made from a negative) since it isnecessary to start with a halide in order to sulfide the sound track. Ifit were desired to form a negative sound track by this method, it wouldbe necessary to remove the silver halide after negative development andrehalogenize the metallic silver in order to obtain a silver halide uponwhich the sulfiding bath could operate.

According to the present invention, the negative silver image which isformed in the sound track by first development is locally converted inthe sound track area to ametallic or metal salt image which will survivethe the subsequent processing baths to which the picture area has to be.

first development of the negative image. For this purpose a motionpicture film may be squeegeed by air or mechanical means to removeexcess moisture immediately after the first development. edge of thefilm where the sound track is present to convert the sound negativesilver image into an image which is not affected by the subsequentprocessing baths, while leaving the picture area unaffected so that thewhole film may thereafter be processed as usual in subsequent baths.This may be accomplished by dipping the edge of the film carrying thesound image into a gold toning solution, or by an edge applicator suchas that described in our U. S. Patent 2,143,787, granted January 10,1939.

The sound track may be either a negative or a positive, and may-beobtained by printing from a negative sound image. The sound track areamay be exposed only to blue light prior to development, so that in thecase of a three-layer film having a blue-sensitive top layer,- the soundimage is mainly in this layer, thus resulting in improved definition andsound reproduction.

A particularly suitable toning solution is one containing gold chloride,which rapidly causes replacement of the negative metallic silver by goldwhich survives subsequent processing solutions. The toning solution maycontain from 1% to 20% of gold chloride, as a very small amount ofsolution suffices to convert the image. After edge application of such asolution, the film may be spray-washed to remove excess gold solution,the wash water being collected for recovery of unused gold.

To avoid spreading of the toning solution to the picture area, thetoning solution may contain loading agents in order to control itsdifiusion,

as described in our U. S. Patent2,059,887, granted November 3, 1936.Another method is to provide by pre-exposure a black metallic silverline separating the sound picture area, the function of such a linebeing to exhaust the spreading gold solution.

When the sound track is treated by gold toning it has been foundadvantageous to employ for final silver removal a weakly-acidterrocyanide bath or, better still, a copper bromide bleaching bathwhich may consist of a solution of 25 grams of cupric chloride and 25grams of potassium bromide, dissolved in one litre of water.

The gold toning method described in this specification may be used withvarious multi-color processes one of which is described in our prior Atoning solution is then applied to the patriifanaa'z'e; granted April'5, 1938. 1' Our'method may, however, be used with other color processesand itis to be understood that our invention is limited only by thescope of the appended claims. 7

We claim: i, 1. The method of forming sound and natural color pictureimages in a film having a plurality of layers sensitive to diflferentspectral regions on.

one side of a support which comprises forming a metallic silver image inthe sound area of the film, converting only the silver sound image tometallic gold by treatment with a' gold toning solution, and subjectingthe film to a series or exposure and color development steps to producesilver and dye images in the layers, th color development being one inwhich a color forming compound couples with the oxidation product of thedeveloper and in which the gold sound image is not affected, and thenremoving the silver images formed in the various development stepswithout afiecting the gold or the-dye images.

2." The method of forming soundand natural color picture images in afilm having a. plurality of layers sensitive to different spectral.regions Y on one sideof a'support which comprises form-' ing a metallicsilver image in the sound area of the film, converting only the silversound image .tometa-llicgold by treatment with a gold chloride solution;and subjectingthe film -to a series of 1 2,2 3,009 7 n. M g s 3. Themethod or formingsound and new color picture images in a film having aplurality,

of layers sensitive to difierent spectral regions on one side of asupport which comprises forming a metallic silver image in the soundarea of the film, converting only the silver sound image to metallicgold by treatment with a gold toning solution containing from 1% to 20%of gold chloride in waterand subjecting the film to a series of exposureand color development steps to produce silver and dye images in thelayers; the color development being one in which a color formingcompound couples with the oxidation product of the developer and inwhich the gold sound image is not affected, and then removing the silverimages formed in the various develop-- ment steps without afiecting thegold or the dye images.

4. The method of forming sound and natural colorv picture images in afilm having a. plurality of layers sensitive to different spectralregions on one side of a support which comprises forming ametallicsilver image in the sound area of the film, converting only thesilver sound image to metallicgold by treatment with a gold toningsolution, and subjecting the filmto a series of exposure and colordevelopment steps to produce silver 'and-dye images in the layers, thecolor exposure and color development steps to produce silver and dyeimages in the layers, the color development being one in which a colorforming compound couples with the oxidation product of the developer andin which the gold sound -Jimage is not afiected, and then removing thedevelopment being one in which a color forming compound couples with theoxidation product of the developer and in which the gold sound image isnot affected, and then removing the silver images formed in the variousdevelopment steps without afiectingthegold or the 'dye images.

silver images formed in the various-development steps ina' weakly acidferrocyanide bath withou aiifecting the gold or the dye images.

LEOPOLD D MANNES. LEOPOLD GO DOWSKY, JR.

